Silicon, the material of choice of the first (demonstration) microengine, exhibits strong thermal softening behavior at temperatures above 900 K. This thermal softening behavior limits the turbine inlet temperature, which in turn significantly degrades the overall engine efficiency. Previous studies have shown that hybrid structures of silicon and silicon carbide have good potential for improve...

Abstract The effect of dislocation-RE atoms interactions on the creep behaviour has been studied via testing and HAADF-STEM analysis two extruded alloys; Mg–0.5Ce Mg–2Gd (wt%). Almost no Ce are detected in Mg matrix due to low solid solubility faster diffusion rate as-extruded condition. However, Gd solute segregations observed along dislocations hexagonal dislocation patterns. Such can not onl...

For modern creep-resistant steels, ductility is primarily controlled by cavitation, since brittle rupture dominating during long-term service. In recent years, the present authors have formulated fundamental models for nucleation and growth of cavities that been verified to be able describe experiments austenitic stainless steels. These equations, together with dislocation creep, are used in th...

Investigations of the Mantle Transition Zone (MTZ; 410-660 km deep) by deformation experiments and geophysical methods suggest that the MTZ has distinct rheological properties, but their exact cause is still unclear due to the lack of natural samples. Here we present the first direct evidence for crystal-plastic deformation by dislocation creep in the MTZ using a chromitite from the Luobusa per...

Yield strength at ambient temperature and creep resistance between 225 and 300°C were investigated in dilute Al(Sc) alloys containing coherent Al3Sc precipitates, which were grown by heat-treatments to radii in the range 1.4–9.6 nm. The dependence of the ambient-temperature yield stress on precipitate size is explained using classical precipitation strengthening theory, which predicts a transit...

In tensile tests, ?-Mg/C14–Mg2Ca eutectic alloy with a lamellar structure is plastically deformed above 473 K but ruptures before yielding at temperatures below 423 K. This study investigates the effect of ?/C14 interface on creep strength under 40 MPa stress. The curves exhibited three stages: normal transient stage, minimum creep-rate and accelerating stage. rate was proportional to spacing, ...

Available constraints on metamorphic reaction rates derived from the study of natural systems are similar to, or slightly lower than, the bulk strain rates measured in the same rocks. Here, we explore whether this apparent relationship is merely coincidence or due to a more fundamental mechanistic link between reaction and strain. Grain boundary migration accommodated dislocation creep (GBMDC) ...

The high-rate sensitivity of nanostructured metallic materials demonstrated in the recent literature is related to the predominance of thermally activated deformation mechanisms favoured by a large density of internal interfaces. Here we report time-resolved high-resolution electron transmission microscopy creep tests on thin nanograined films using on-chip nanomechanical testing. Tests are per...